1. Field of the Invention
The present invention relates to a recording method for a magnetic recording medium, a recording device for a magnetic recording medium and a magnetic recording medium.
2. Description of the Related Art
In recent years, a demand for a high-density recording has been increased. A property suitable for the high-density recording is also requested for a magnetic recording medium as a recording medium of information. Accordingly, various kinds of improvements are performed on the magnetic recording medium.
For instance, in a linear magnetic tape used for the recording medium of a computer or the like, recording tracks for recording the information in the longitudinal direction of the tape are provided. Distances between the recording tracks are narrowed to improve a track recording density and achieve the high-density recording.
However, when a magnetic head records and reproduces the information, the magnetic head jumps over an adjacent data recording track to move in the direction of width of the tape and access a prescribed recording track. Accordingly, when the distances between the recording tracks are too small, interference is generated between the recording tracks. Thus, the information cannot be precisely recorded and reproduced.
Thus, media having servo signals respectively between the recording tracks of the magnetic tape is developed. In the above-described media, servo signal parts are formed respectively between the recording tracks. Accordingly, the interference between the recording tracks upon recording and reproducing the information and the dislocation (off-track) of a reproducing head from the recording track can be prevented.
Thus, the track recording density can be more improved to achieve the high-density recording. Further, in the media in which these servo signals are recorded, the interference between the recording tracks upon recording and reproducing the information can be prevented, so that output characteristics or overwrite characteristics are improved.
The magnetic recording medium and a recording method for recording the servo signal are proposed in, for instance, Japanese Patent No. 3116531. Further, as DC (direct current) erasing means of the present invention, a magnetic head described in, for instance, Japanese Patent Application Laid-Open No. hei 10-124820, Japanese Patent Application Laid-Open No. hei 10-172109, Japanese Patent Application Laid-Open No. hei 9-282608, and Japanese Patent Application Laid-Open No hei 7-37225 can be used.
Further, a metallic thin film type magnetic recording medium and a method for producing a metallic thin film type magnetic recording medium are proposed in, for instance, Japanese Patent Application Laid-Open No. 2003-296919, Japanese Patent Application Laid-Open No. 2003-85742, Japanese Patent Application Laid-Open No. 2003-45018, Japanese Patent Application Laid-Open No. 2003-6851, Japanese Patent Application Laid-Open No. 2003-346329, Japanese Patent Application Laid-Open No. 2002-367135, and Japanese Patent Application Laid-Open No. 2002-245611.
In the magnetic tape having the high recording density, the servo signals are very important, so that all the servo signals need to have a high quality. Particularly, when the output of the servo signal is low, the position of the recording and reproducing head cannot be properly controlled. In an extreme case, a servo head undesirably misses the servo signal. Further, when time is not precisely recorded (jitter is large), the same problem may be possibly generated.
In a tape for storage having a higher recording density than that of a conventional tape, the thickness of a magnetic layer is apt to be reduced. In a conventional particulate type recording medium, when the thickness of a magnetic layer is about 0.15 μm to 0.20 μm, a sufficient output of a servo signal has been obtained.
In a conventional servo signal recording system, only servo signal parts are magnetized in the directions as shown arrow marks as illustrated in FIG. 9A and no signal parts are not magnetized. Accordingly, there is not a boundary area in which a magnetized direction is completely inverted, so that obtained signals are low in S/N ratio as shown in FIG. 9B.
Therefore, the media in which the thickness of the magnetic layer is smaller than 0.13 μm due to the high density recording can obtain only about half an output by the conventional servo signal recording system, which causes a great trouble for an accurate reproduction of the servo signals.
Further, what is called an evaporated tape in which a metallic thin film is directly formed on a base film also has an important problem to improve a servo output.